Three characteristics of Earth's orbital motion change slightly over long periods of time. These cyclical changes cause differences in the amount of sunlight the Northern and Southern Hemispheres receive. Analysis of deep-sea sediments has shown that these changes are closely associated with climate change.

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Precessionthe
orientation of Earth's axis of rotation.

Eccentricitythe
shape of Earth's orbit around the
sun.

Obliquitythe
angle between Earth's axis and a line
perpendicular to the orbital plane.